Wheat residue loss from fields under no-till management.
Stott D.E. | Stroo H.F. | Elliott L.F. | Papendick R.I. | Unger P.W.
To successfully implement no-till crop management systems for winter wheat (Triticum aestivum L.), knowledge is needed on how rapidly large residue fragments are lost. At five sites in Washington, Texas, and Indiana, losses of surface-managed winter wheat residues were measured over time. Sites were sampled periodically by using grab samples to determine weight loss per unit area. Thirty weeks after harvest, residue weight losses ranged from 35 to 42% and, after an additional 5 wk, losses ranged from 38 to 55%. Snow cover provided insulation for residues, allowing decomposition to continue during winter when sufficient moisture was present. On chemical fallow plots, there was a 50 to 80% loss after a year. On plots seeded with a no-till spring crop, residue losses ranged from 81 to 88% by harvest time. Contributions of various sources of residue mass loss are discussed. Effect of residue loading rate was also determined; the highest residue loading rate exhibited the smallest losses. After a year, there was 75, 72, and 50% residue weight loss from the 1680, 3360, and 6720 kg ha-1 plots, respectively. At three sites, changes in the surface area covered by the decomposing residues was measured. Initial coverage from harvest ranged from 93 to 99%. Coverage declined to between 85 and 95% after winter.
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